Built around 1510, as the principal place within the castle for ceremonial and state occasions. Standing on the South side of Crown Square,
it was converted into barracks during Cromwell's occupation in the 1650s, with further alterations in 1737, including intermediate floors,
allowing the 312 men to be housed here. Following the construction of The New Barracks in 1799 the Great Hall was converted for use as a military hospital,
remaining so until 1887 when the hospital moved to a converted storehouse. Restoration followed soon after.

The roof and the crow-stepped gables are the only original features to have survived the many changes this building has seen through the centuries.
The whole of the interior was designed by Hippolyte Blanc during his restoration in 1887.